Techniques for efficiently producing petrochemical products and intermediate products thereof from a fluid catalytic cracked oil fraction are widely known to be (1) subjecting fluid catalytic cracked gasoline to catalytic reforming thus preparing reformate which is then separated, thereby producing aromatics, (2) subjecting fluid catalytic cracked gas oil to hydrodesulfurization thus preparing low-sulfur gas oil products, and (3) subjecting fluid catalytic cracked gas oil to hydrocracking thus preparing low-sulfur gas oil, LPG and naphtha.
However, the technique (1) is limitedly applied to the fluid catalytic cracked gasoline, in particular, only a middle boiling point gasoline fraction having a low octane number, and is unable to produce LPG and low-sulfur gas oil, the demand for which is increasing.
Although the technique (2) may advantageously correspond to the demand for low-sulfur gas oil resulting from hydrodesulfurization of the fluid catalytic cracked gas oil which may be used alone or in combination with light gas oil produced through atmospheric distillation of crude oil, it cannot be applied to an increase in the demand for LPG and aromatics.
The technique (3) is advantageous because it may correspond to an increase in the demand for low-sulfur gas oil having a high cetane number and LPG and may be used to produce naphtha the demand for which is continuously increasing. However, with this technique it is not easy to control severe conditions of operation, and thus it cannot be easily adapted to stepwise enhancement of standard of gas oil products, the consumption of hydrogen is much greater compared to the technique (2), and also it is incapable of producing aromatics.